How can you find all MD bus_dmamap_create() implementation in whole
MI/MD source tree?

I would suspect by a similar process of finding the calls in
the source tree :)
There are 698 references to bus_dmamap_create through the
tree, 29 are defines, 486 are of the form 'if (bus_dmamap_create'
or 'foo = bus_dmamap_create', and a fair chunk of the rest are
in printfs, comments, or other misc areas.
I'd estimate there would be fewer references to check in the
implementations than the callers.

the problem is that a simple grep doesn't give you all implementations.
Some of then are referenced though function pointers; finding all of them
requires more work.

Going off on a small tangent here - would there be any sane way of
having code (under DEBUG) which after a bus_space implementation
is defined would automatically call it with a known bad set of
parameters and check the return values? Or possibly have a kernel
module which could do the same? Some form of 'atf for the kernel'?
--
David/absolute -- www.NetBSD.org: No hype required --